7.11 Repeating a Command

Many simple commands, such as those invoked with a single key or
with M-x command-name <RET>, can be repeated by
invoking them with a numeric argument that serves as a repeat count
(see Arguments). However, if the command you want to repeat
prompts for input, or uses a numeric argument in another way, that
method won't work.

The command C-x z (repeat) provides another way to repeat
an Emacs command many times. This command repeats the previous Emacs
command, whatever that was. Repeating a command uses the same arguments
that were used before; it does not read new arguments each time.

To repeat the command more than once, type additional z's: each
z repeats the command one more time. Repetition ends when you
type a character other than z, or press a mouse button.

For example, suppose you type C-u 2 0 C-d to delete 20
characters. You can repeat that command (including its argument) three
additional times, to delete a total of 80 characters, by typing C-x
z z z. The first C-x z repeats the command once, and each
subsequent z repeats it once again.